Build table schemas

[HannahBurgoyne]

• [ ] create users table
• [ ] create crew_users intermediate table
• [ ] create crew table
• [ ] create events table
• [ ] ensure all tables have the correct relationships as shown in our database diagram
• [ ] run migrations

[laura-ellen-harris]

Figma Wire Frame:

https://www.figma.com/file/Q1zRcTMyyRJ2iEDl7Dyk6K/Untitled?type=design&node-id=0-1&mode=design&t=I2nROMSM9gICgQIy-0